1. Technical Field
The present invention relates to a discharge lamp lighting device, a method of controlling a discharge lamp lighting device, and a projector.
2. Related Art
As a light source of a projector, there is used a discharge lamp such as a high-pressure mercury lamp or a metal halide lamp. In the discharge lamp, the shape of an electrode varies due to consumption of the electrode caused by discharge. If a plurality of projections grows on a tip section of the electrode, or irregular consumption of the electrode body progresses, migration of arc source or a variation of arc length is caused. Such phenomena cause lower luminance of the discharge lamp, and lead to shorter life of the discharge lamp, and therefore, are not preferable.
As a method of solving this problem, there is known a discharge lamp lighting device driving the discharge lamp using alternating currents with frequencies different from each other (see e.g., JP-A-2006-59790 (Document 1)).
However, even when driving the discharge lamp using the alternating currents with different frequencies, there is a possibility that stationary convection due to the emission is formed inside the discharge lamp to cause uneven consumption of the electrode or uneven precipitation of the electrode material.